I'm making an Arithmetic Error, Electrostatic force diagrams

1. The problem statement, all variables and given/known data
Three charged particles are placed at each of three corners of an equilateral triangle whose sides are of length 2.7 cm . Two of the particles have a negative charge: q1 = -6.0 nC and q2 = -12.0 nC. The remaining particle has a positive charge, q3= 8.0 nC . What is the net electric force acting on particle 3 due to particle 1 and particle 2?

So the only thing left was to find F(2on3) in the same way I found F(1on3).
Arranging the problem so that q3 was at the origin, q1 was at the top of the triangle and q2 was along the x-axis, I found this:

1. The problem statement, all variables and given/known data
Three charged particles are placed at each of three corners of an equilateral triangle whose sides are of length 2.7 cm . Two of the particles have a negative charge: q1 = -6.0 nC and q2 = -12.0 nC. The remaining particle has a positive charge, q3= 8.0 nC . What is the net electric force acting on particle 3 due to particle 1 and particle 2?

So the only thing left was to find F(2on3) in the same way I found F(1on3).
Arranging the problem so that q3 was at the origin, q1 was at the top of the triangle and q2 was along the x-axis, I found this:

Really? I thought i'd looked it up and found it was the same, math-wise, just different in definition. My mistake I guess...
Scientific calculators only offer the tanh function though. Is that because they expect you to simply find Tan(Θ) and then find 1/x?

Really? I thought i'd looked it up and found it was the same, math-wise, just different in definition. My mistake I guess...
Scientific calculators only offer the tanh function though. Is that because they expect you to simply find Tan(Θ) and then find 1/x?

Oh wow, yes I can see now how the hyperbolic functions are so much not the same thing...
Okay, I need to find tan^-1(Θ) in order to solve this problem and get me the angle between the force components? Sounds pretty straightforward now. I was making a mistake with my calculator because I didn't distinguish the notations.